WFT的压力影响因素分析及渗透率计算方法的改进

电缆地层测试器(Wireline Formation Tester)的压力测量，主要受到来自仪器的存储效应和测量环境的表皮效应的影响，通过三维有限元数值模拟程序定量的描述了存储效应和表皮效应与压力的关系。结果表明，受存储效应的影响，在低渗透率地层测量的压力，没有稳定的压力降，不经过校正，不能进行渗透率的计算；受表皮效应的影响，测量的压力降只有原来的1／3，这使地层的渗透率被低估。为了消除影响渗透计算的因素，研究了电缆地层测试器的量纲为1解释图版，对存储效应和表皮效应进行了校正，提高了渗透率计算精度。

Improvement in permeability computation and pressure effect of WFT

Measuring pressure with wireline formation tester is mainly subjected to the storage effect from the tool and skin effect from the environment. This paper studies the relationship of the pressure with the storage and the skin by 3D FEM. The pressure due to storage at the low permeability formation shows no steady drawdown, which renders it impossible to calculate permeability. The pressure drawdown affected by skin on all kind of formations only is third of the original pressure. These make the computing permeability lower. The paper developed the dimensionless chart of WFT to reduce the effects. The chart corrected the storage effect and the skin effect. It is better for the computing permeability.